DS12887A Datasheet, PDF (6/19 Pages) Maxim Integrated Products – Real-Time Clock

DS5000(T)
PROGRAM LOADING CONFIGURATIONS Figure 3
PROGRAM
ADDRESS
V_CC GND
DS5000
A7–A0
P1.7–
P1.0
P0.7–
P0.0
D7–D0
PROGRAM
DATA IN/VERIFY
DATA OUT
A11–A8
P2.3–
P2.0
P3.7–
P3.4
A15–A12
PROGRAM
ADDRESS
PROGRAM
CONTROL
EA/V_PP
ALE/PROG
P2.7
P2.6
P2.5
XTAL1
XTAL2
RST
PSEN
R<2K
11.059 MHz
V_CC GND
DS5000
P1.7–
P1.0
P0.7–
P0.0
P2.5–
P2.0
P3.7–
P3.2
P2.6
P2.7
TXD
RXD
DRIVE/
RCV
RS232C
XTAL1
XTAL2
RST
PSEN
R<2K
PARALLEL
LOADING
Table 1 summarizes the selection of the available Paral-
lel Program Load cycles. The timing associated with
these cycles is illustrated in the electrical specs.
SERIAL BOOTSTRAP LOADER
The Serial Program Load Mode is the easiest, fastest,
most reliable, and most complete method of initially
loading application software into the DS5000(T) nonvol-
atile RAM. Communication can be performed over a
standard asynchronous serial communications port. A
typical application would use a simple RS232C serial in-
terface to program the DS5000(T) as a final production
procedure. The hardware configuration which is re-
quired for the Serial Program Load mode is illustrated in
Figure 3. Port pins 2.7 and 2.6 must be either open or
pulled high to avoid placing the DS5000(T) in a parallel
load cycle. Although an 11.0592 MHz crystal is shown
in Figure 3, a variety of crystal frequencies and loader
baud rates are supported, shown in Table 2. The serial
loader is designed to operate across a three–wire inter-
face from a standard UART. The receive, transmit, and
ground wires are all that are necessary to establish
communication with the DS5000(T).
The Serial Bootstrap Loader implements an easy–to–
use command line interface which allows an application
SERIAL
LOADING
program in an Intel hex representation to be loaded into
and read back from the device. Intel hex is the typical
format which existing 8051 cross–assemblers output.
The serial loader responds to single character com-
mands which are summarized below:
COMMAND
C
D
F
K
L
R
T
U
V
W
Z
P
G
FUNCTION
Return CRC–16 checksum of em-
bedded RAM
Dump Intel Hex File
Fill embedded RAM block with
constant
Load 40–bit Encryption Key
Load Intel Hex File
Read MCON register
Trace (Echo) incoming Intel Hex
data
Clear Security Lock
Verify Embedded RAM with in-
coming Intel Hex
Write MCON register
Set Security Lock
Put a value to a port
Get a value from a port
021998 6/19